Category: SQL 08 R2

QGIS 2.8.1 Getting Shape Files into SQL Server 2008 Express R2

For digital mapping the shp extension is the equivalent of csv files – A significant amount of information is still held in shape files and even if it is not, nearly every GIS package can export to shape format. It’s therefore pretty vital that you understand how to get this format into your backends.

Turns out QGIS 2.8.1 comes with a very handy excecutable called ogr2ogr.exe
On my computer this was downloaded with my installation of QGIS 2.8.1 and placed in the the following directory

C:\Program Files\QGIS Wien\bin

It looks like this executable has been a part of the the download for sometime so if you are on a different version of QGIS I suspect the file will be on your machine but in a directory other that QGIS Wien – whatever your version is.

If in doubt a simple search on ogr2ogr should give you the location.

From the command prompt you need to either navigate to the location of ogr2ogr.exe or place the full path into the instruction. In the following I have navigated to the appropriate directory using change directory command at the prompt. I then input the following.

ogr2ogr -overwrite -f MSSQLSpatial "MSSQL:server=MARK-LENOVO\SQLEXPRESS;database=Geodatabase;trusted_connection=yes" "C:\Users\Mark\Documents\shp\polygon\n_america.shp"

On return it will start to import the information creating a new table in your SQL Server instance within the database listed in your parameter string. It looks like it just names the table the same as the shape file, I suspect if that name already exists as a tablename in SQL Server that table will be overwritten with the new shape file. Also note that the import process can take a fair bit of time for large files so be patient. I tested it initially with a small import which it did relatively quickly, I then went and hit it with 500 thousand records and it took a little over 2 hours. Still good to know that it can cope.

Once you have imported the information into SQL you should perform some form of spatial indexing on the table.
I have noted that layers that have spatial indexing are drawn differently than non spatial indexed layers. Layers with spatial indexes are drawn in more rapidly all over the district much like a spray from a can. Non spatial indexed layers appear on screen slower as if painted from one side to the other.

Setting up a Blank SQL Server Spatially enabled Table using Microsoft SQL Server Management Studio 2008R2 Express and displaying it in QGIS 2.8.1

Programs used;

1- SQL Server 2008R2 Express
2- SQL Server Management Studio 2008R2 Express
3- QGIS

The example uses UK national grids coordinates to create a Triangle Polygon in a SQL Server Table

I’ve previously written that while we’ve had spatially enabled SQL Server for over 5 years I constantly come across line of business applications that although using SQL Server have not and do not intend to spatially enable the application. This is undoubtedly because of the difficulty in re-designing legacy systems actively in use and because the benefits although significant are not generally requested by all but the most knowledgable of colleagues.

While I understand this legacy system reasoning spatially enabled databases are the future so its just a matter of when and not if an application will require alteration. Understanding it in this context makes it really a requirement to start seriously planning for its inclusion.

Developerers creating new applications however should always consider spatially enabling relevant tables from the start even if it is not specked by the client/colleague. It being so much easier to spend a couple of minutes future proofing the schema of a new born database rather than hours trying to retrofit a live in production back end.

Firstly it’s important to understand what a geodatabase in SQL Server actually is.
Really it is a normal database which has one table that has a field that has a geometry or geography value type. In this example I will use desktop QGIS 2.8.1 to display the resulting geometry but any other digital mapping package that can link to SQL Server could be used. SQL Server also has a very rudimentary Mapping Display but you will need something better if you want to manipulate boundaries visually.

Many digital mapping products have plugins that will create Geodatabases and tables however I haven’t seen one for QGIS. I really wanted to be able to create spatial SQL tables on my own without recourse to paid tools directly in SQL Server Management Studio. So here’s my method of creating blank polygon table whose geometry is ready to be read and edited in QGIS or any other digital mapping system just using SQL Server Management Studio Express 08R2.

Steps
1. Create a new Table
2. Ensure the table has an identity Key that increments
3. Create a geometry column
4. Write a query that updates the geometry column

UPDATE T001Sites SET Coordinates=geometry::STGeomFromText(‘POLYGON((301804 675762,295789 663732,309581 664870,301804 675762))’,27700)

You will note that there are four coordinates here (each coordinate being a pair of numbers )
The first coordinate and last are the same this is required by SQL to ensure that the polygon is closed.

The 27700 number is the Spatial Reference System Identifier (SRID) – it is a unique value used to unambiguosly identify projecttion. 27700 is the unique identifier for the United Kingdom National Grid and represents the coordinates my example refer to. The spatial reference identification system is defined by the European Petroleum Survey Group (EPSG) standard which is a set of standards developmed for cartography surveying etc and owned by the Oil and Gas Producers Group list here; http://www.epsg-registry.org/

The above coordinates display a triangle in West Lothian near Edinburgh

5. Set up the connection to SQL Server Instance

Ensure the box marked “Only look in the geometry_columns metadata table” checkbox is unchecked. By default this is checked and if the geometry_columns table does not exist you will get an error message.

QGIS-SSMS-Connection

6. Display the table and edit as appropriate.

Select the table then hit the Add button

QGIS-SSMS-TableReadyforDisplay

And here is the SQL Server table in QGIS ready to be added to or edited.
QGISshowingSQLServerPolygon

Enabling Geospatial integration in applications.

Despite the fact that spatially enabled databases have been around pretty much everywhere for quite sometime there’s still a heck a lot of enterprise applications out there that are not using the feature even though their backends support it.

SQL server has had the facility since 2008 , Oracle has it as well although it is with the expensive Oracle 11g Enterprise edition.

So if its available why are so many applications not using it?

Well one of the reasons is that many of the applications which would benefit from introduction are central to organisations and were in existence long before the feature was available in backend databases. So why not introduce it as an update? Well the problem is a geospatial attribute is a form of primary key more accurate than the often completely arbitrary primary keys that most tables will take as their reference. Adding it is likely to require not just the addition of a geospatial attribute which will be a defacto primary but potentially adding a full table not as a child but as a parent to the previous parent records – the former parent records requiring the addition of foreign keys that relate to their parents.

As most of you know altering primary keys in tables is pretty much equivalent to transplant surgery for a database.
Totally wiping a primary key and starting with a different primary key that needs to then be captured for itself and related back to its children is if anything several orders of magnitude worse than that..

Doesn’t sound good does it.

This is another case where if you have paying clients or you have a purchased product that isn’t going to happen until there is an outside force from a competitor. But the benefits are legion. As it stands most information in geographical systems is flat files that has to be updated directly within either the web gis or a gis desktop. These programs are really terrible making an application fully geospatial by design allows the UI you to display the geographical information in the GIS – web or desktop and related information in forms which often have vastly improved searching / linking to other systems drop down boxes well pretty much everything.

Leave plenty of time for it but would be proper automation. Too many GIS systems are mirrored copies of a database that periodically have to be updated. This is not the long term optimum.

Attaching Databases to SQL Server 08R2 Express

jigsaw2
It should be noted that the following although the easiest way to get a new database into an instance it should not be used in a production environment. In fact doing so may get you sacked. If experimenting though this method should be fine. If in doubt seek help as in a production environment you would want to look through all the code before attaching anything into an instance.

Go to SQL server management studio and on the Databases tree
Right click and select
Attach…..

Attach database window should appear which will allow you to use the Add… button to navigate to the
\Data\ subdirectory where all the sql server databases are held.

IMPORTANT – prior to loading a file in the database will have needed to have been DETACHED and you should always move anything mdf file that you are wanting to put into a database into the data subdirectory.
This ordinarily is done by going to database in question scrolling down to the database and right clicking on the database

Tasks > – Detach…

WARNING
If a database has not been detached properly it may NOT be possible to re-attach the database this is of course a security feature. So experimenting with simple moving files about will not work…

The listed code below does it at command line but the above works in SSMS

The default location for databases in SQL 08R2 Express is
C:\Program Files\Microsoft SQL Server\MSSQL10_50.SQLEXPRESS\MSSQL\DATA

The default location for database in SQL 2012 is
C:\Program Files\Microsoft SQL Server\MSSQL11.[InstanceName\MSSQL\DATA

Stopping and Starting SQL Server Instance 08R2 Express

startstop

Simply within SSMS right click on the instance and hit STOP and
To start an instance if you are still in SSMS you can simply right click and hit start

Note if you stop a SQL Server instance from within SSMS AND then exit SSMS and try and go back in you will be denied as SSMS is unable to connect to a service that is not up and running.

In such a case to restart the instance you need to go to SQL server configuration manager and click on the instance and restart from there.
In Windows 8.1 you can get to config manager by using the search facility.

Windows 10 Alternative
Hit the search ring
type in services.msc
A new dialog should appea that will have Services(Local) with several columns – Name / Description / Status / StartupType
You want the Status to be Running
Use the mouse to highlight SQL Server (MSSQLServer) and then right click
Start

Your server should now be running

Allowing sa login and altering password SSMS SQL 08 R2 Express

password-security

Recently I installed SQL Server 08 R2 Express.

As part of the standard installation the sa login is disabled as default.

Clearly although this is a useful security feature it is a bit awkward if you are wanting to undertake certain tasks and as part of the installation this security feature is in no way obvious.

So what do you do to re-enable it?

Firstly log into SSMS under the machine windows login.

Go to the Security section of the server (not any of the databases) and expand the Logins branch. SA the system admin should be listed and if it is disabled it will have a small red down arrow next to it.

To re-enable highlight sa and right click

Select properties

Select Status

now alter the following
Permissions to connect to database engine
Set this to GRANT

Login
Set this to Enabled

Now highlight instance itself and right click and go to properties.
Within server properties highlight Security.
And change set server authentication to
SQL Server and Windows Authentication mode.

You should have sa login now enabled – don’t worry if sa still has a small red arrow next to it the SSMS client needs to be refreshed to see changes to set up.

If you want to change the password for the SSMS server I would recommend running the following.

ALTER LOGIN sa ENABLE ;
GO
ALTER LOGIN sa WITH PASSWORD = 'DifficultPass9£' ;
GO

Note you can enforce the requirement for a strong password within the same security section of the sa login if you require.